Velocity fluid vacuum seal, method and apparatus



Aug. 10 1926.

O. MINTON VELOCITY FLUID VACUUM SEAL, METHOD AND APPARATUS OriginalFiled Nov. 30, 1920 5 Sheets-Sheet 1 1h l| mm mm N I: 1' a l III :I I i!ii I 'I I II}:

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'INVENTOR akgfzzm. ATTORNEY Aug. 10 1926. 1,595,492

0. MINTON VELOCITY FLUID VACUUM SEAL, METHOD AND APPARATUS originalFiled Nov. 30. 1920 3 Sheets-Sheet 2 Q Q J IN VENTOR Aug. 10 1926.

O. MINTON VELOCITY FLUID VACUUM SEAL, METHOD AND APPARATUS OriginalFiled Nov. 30, 1920 3 Sheets-Sheet s Z INVENTOR BY- 2 Q4 ATTORNEYPatented Aug. 10, 1926.

UNITED STATES PATENT. OFFICE.

OGDEN HINTON, OF'GBEENWICE, OOmUlICUT.

VELOCITY FLUID vacuum SEAL, lmrnon m arrmrus.

Original application filed November 80,1920, Serial ll'o. 427,488.Divided and this application fled July 25, 192;, Serial llo. 577,304;

This application is a' division of my copassages having restricted areasInerg- 7 pending application Ser. No. 427 ,4361 filed November 30, 1920,Case L.

My invention relates to the method of 6 treating materials in a Vacuum,and more particularly to the method of protectin the opening or openingsinto the vacuum c amber through which opening or openings the materialto be treated'is introduced" and 10 withdrawn from the chamber} Myinvention relates more-particularl to a vacuum seal maintained by theapphcation of.velocity'head, i. e.', the difference 111 pressure betweenthe atmosphere and vacuum being balanced by the velocity head of thesealing medium. \Through this -sealthe material to be treated in thevacuum chamber is passed in any suitable manner.

My invention further relates more. par-- ticularly to the method ofdrying sheet ma;

terial, as a continuous web'of paper either coming fromthe web end of apaper machine, or from a sizing vat, or from a coloring apparatus,coating or impre ating machine, or printing machine or irectly from aroll of wet paper. 7

My invention further relates to a vacuum apparatus, including a vacuumchamber having'passages extending from the said vacuum chamber and opento the. atmosphere. These passages are protected by velocity fluid sealswhich prevent the ad-.

mission of air into said vacuum chamber as the material to be treated isintroduced 1;? and withdrawn through said seal-s.

My invention further relates to employing any suitable fluid, in thevelocity seals, which has no aflinity for or deleterious effect upon thematerial to be treated in the vacuum chamber. I may for examplensemercury or an amalgam, or air, or steam or water or similar fluid havingthe characteristics above stated. In the caseof water', if thematerialto be treated should, for;

' example, be a web of paper to be dried I may protect the webby'endless rubber or waterproof felts or other similar guards.My'invention further relates to employ- Benewcd l'ebrqary 17,- 1986.

ing lnto progressivel larger areas between the atmosphere an theinterior of the vacuum chamber, forming in efl'ect Venturi nozzles,through which the fluid of the velocity fluid seals flows.

7 My invention further relates to a vacuum chamber provided withentrance and exit opemngs aving a. plurality of restricted passagessimilar to a plurality of Venturi nozzles connected in series.

My invention further relates to collecting the fluid of the velocityfluid seal and again using it in the seal, or if the fluid is steam,collecting and using it in the dryers,

or using it to heat the building; or I may condense it or otherwisedispose of it.

,Myinvention further relates to certain steps, and combinations ofsteps, also to certain elements and combinations of elements, wherebythe method or processes herein described may be carried out, as well asto certain details of construction, all of which will be more fullyhereinafter described in the specification and pointed out in theclaims.

I have shown in the drawings diiferent forms of apparatus which may beused to carry out my improved method, but it is to be distinctlyunderstood that my invention isnot to be confined to the particular formof apparatus, shown by way of illustration.

In the accompanying drawings the same reference numerals refer tosimilar parts in the several figures.

Fig. 1 is a diagrammatic view partly in section of the simplest form ofmy invention;

. Fig. 2 is a diagrammatic view similar to Fi 1, except showing dryingrolls or cy nders in the vacuum chamber;

Fig. 5 is a detail vertical section showing a Web of paper or similarmaterial protected by endless rubber or waterproof felts or similarguards;

Fig. 6 is one of a plurality of ordinary steam radiators which may beconnected to the chambers 11, 11 when steam or hot water is employed inthe velocity seals.

I will describe the simplest form of my invention first, that showndiagrammatically in Fig. 1.

The vacuum chamber A has a vacuum maintained therein in any suitablemanner by connecting the pipe 1 with any suitable exhausting apparatus.This vacuum chamber has two passages 2, 2 open to the atmosphere.Through these passages the material to be treated in the vacuum chamberA is introduced and withdrawn. Of course, if the passages were leftunguarded the vacuum in the vacuum chamber A would be broken.

My invention broadly consists in guarding the passages to the atmosphereby velocity fluid vacuum seals. the velocity of the fluid beingsutliciently high to prevent any air working past the velocity seal intothe vacuum chamber.

In my invention suitable material may be introduced into and withdrawnfront the vacuum ehan'iber A through my velocity fluid seals 3, It maybe treated in any suitable manner within the vacuum chamber A. It may befed through the vacuum chamber continuously or not. I have shown by wayof example the material in the form of a continuous web 7 which passescontinuously through the vacuum chamber A and the velocity fluid vacuumseals 3, 3. This web 7 may be dried in the 'acuum chamber, or coated.colored, impregnated or treated in any other suitable manner, and may befed into and out of the vacuum chamber in either direction as indicatedby the arrows.

These passages 2, 2 have restricted areas 4, 4. Connected with theserestricted areas are nozzles 5, 5. The area of the passages 2, 2increases at 6, 6 adjacent the restricted areas 4. 4.

Fluid which has no affinity for or deleterious effect upon the web 7 orother material treated. is forced into the chambers 11, 11 through thenozzles 5 at sullieient velocity to prevent air passing through therestricted area 4 and getting into the vacuum chamber A. The velocityrequired will depend on the vacuum maintained in the vacuum chamber andthe fluid used for the seal. Preferably I employ as near a perfectvacuum as I can maintain, usually about 28 inches of mercury.

Whatever fluid is used passes through the nozzles 5 with comparativelyhigh velocity.

As the fluid reaches the portion 6 of com- )tll'fltlVtBl Y lar e areaits velocit is reduced. i .l h y .l he passage 2 with its restrictedarea 4,

' nozzles 5 and portions of greater area 6 is in effect a Venturi typenozzle. The passage 2 is of course wide enough to permit the freepassage of the widest web or other mat erial 7 to be passed into and outof the vacuum chamber A.

The fluid which I employ for my velocity fluid vacuum seal may bemercury or an amalgam or similar material, steam. water, air or similarfluid. If water is used as the fluid and the material treated a web 7 ofpaper to be dried, then I may protect the paper by rubber or otherwaterproof endless felts [(3, 17, Fig. 5.

1f air used as the fluid of the seal it will be permitted to pass intothe atmosphere. if water be used it may be collected in the chamber llvand drawn off by the pipe 12 to be used again or allowed to run towaste. If mercury or amalgam be 'used it would be collected in thechamber 11 and pass through the pipe 12 to be used again as shown, forexample, in the other figures of thedrawiugs. 1f the fluid be steam, itwould pass from chamber 11 through the pipe 12 to be used as the heatingmedium in the steam drying cylinders or drums 5 shown in the otherl'igures of the drawings,

or it may be used to heat the building by using one or more steamradiators 13, or the pipe 12 may be connected to a vacuum pipe orcondenser.

My invention is particularly adapted to be used in connection withdrying sheet material in the fornrof-paper, though it is to bedistinctly understood that it is equal- 1y applicable to and coversdrying sheet material in the form of textile fabrics, as for example,drying such fabrics after they have been washed or bleached or dyed, orotherwise treated by a liquid of some description.

I have shown my invention in connection with drying a web of paper inthe other figures of the drawings.

In these other figures A is a vacuum chamber, in which I mount aplurality of drying drums or cylinders 14, 15, usually five being usedas in my original application Ser. No. 427.136 of which this is adivision. The wet web of paper 7 coming directly from the wet end of apaper machine, or from a coloring apparatus, coating machine, printingmachine, or directly from the roll of wet paper, is fed into the vacuumchamber A. It is preferably, though not necessarily. received betweenthe upper traveling felt 16 and the lower traveling felt 17. These felts16 and 17 with the interposed web 7 of paper or similar material are fedinto the vacuum chamber A in any suitable manner, through a duplicatevelocity seal Sill shown in Figs. 1, 3 or 4 of this ap lication, or oneof the forms of velocity s s shown in said parent application Ser. No.427,436. The web 7 is then dried by passing over the one or more dryingdrums or cylinders 14, 15, or dried in any other suitable manner in thevacuum chamber A.

I may not employ felts. Wnen I do \use them, I preferably arrange themas in said parent application. As partly shown- 1n Fig. 3, the upperfelt 16 passes over the drying drum or cylinder 14 and meets the lowerfelt 17 after the latter has passed over the guide 18. Both felts 16 and17 with the 1nterposed Web 7 pass over the drying drum or cylinder 15and out through the exlt passage, thence under the guide roll 19, theupper felt being led back over the vacuum chamber A to the entrance tosaid chamber, while the lower felt 17 passes over the guide roll 20 andback to the same entrance passage under the vacuum chamber A.

In the form of my invention shown in Fig. 3. the restricted passage 21is, connected with nozzles 22, 22. The fluid 29, as for example, mercuryis drawn from the felt ro-ll housing 23 by the suction pipe 24 to thepressure pump 25, operated by the motor 26. and is forced, through thepipe 27, into the nozzles 22, 22. Asthe mercury or sim lar materialpasses through the restricted area 21, t is moving with considerablevelocity, which velocity is reduced as the portions of increased area 28are reached. The restricted area connected wit-h the passage of largerareas forms a Venturi type nozzle.

The liquid 29 of the seal is-forced through the restricted area 21 ofthe passage with just sutflcient'velocity to balance or slightly exceedthe pressure of the atmosphere upon the liquid seal, which pressure ifnot countel-acted. would cause the fluid of the seal to back up withinthe vacuum chamber.

The drying drums or cylinders 14 and 15, as well as the others notshown, are all I preferably driven at the same speed that the web istraveling and are heated by steam in any suitable manner.

In Fig. 4 I have shown afurther modi-- fication of my invention in whichI employ a plurality of nozzles and restricted areas connected inseries.

In th s form of my invention the interior of the vacuum chamber A isconnected with p the felt roll housing 30 with a passage 31,

and provided with different sets of nozzles 32, 33 and 34. and differentrestricted areas and enlarged areas all connected in series.

The mercury or similar material is taken from the barometric seal orreservoir 35 by the suction pipe 36 and is pumped by the pump 37 throughthe nozzles 34. The fluid has considerable velocity as it passes throughthe restricted area 39, its velocity falling as it reaches the portion40 of larger the second large area 44. The suction pi e 45 of the thirdpump 46 is connected with t e large area 44 and pumps the fluid throughthe nozzle 32, the fluid then passing through the third large area 47into the felt roll housing 30. The pumps may be driven in any suitablemanner I have shown them driven, for example, by the motor 48 throughthe common shaft 49. The pipe 50 connects the felt roll housing 30 withthe barometric seal or reservoir 35.

While I have shown three sets of nozzles and'rcstrizited and enlargedareas, for purpose of illustration, it is of course to be understoodthat any number desired may be liquid seal 51, which will prevent anyofthe liquid working back into the vacuum chamber A. Should the pressureexerted by the pumps momentarily not be sufiicient to balance. theatmospheric pressure on the liquid seal 51, a small quantity of theliquid may work into the Well 52. From this vvell 52, it will beimmediately withdrawn by the pipe 53 extending into the reservoir 35without breaking the vacuum in the vacuum chamber A. It will, therefore,be seen that in this form of my invention the reservoir 35 acts normallysimply as a reservoir for the liquid to be pumped through thediflerentre stricted passages or Venturi type nozzles. It is so locate-d,however, that it also performs the function of a barometric seal, andwill withdraw any liquid thatmight momentarily and accidentally workinto the well 52.

My method possesses many advantages not present in processes heretoforeused for many years in the drying of paper.

The evaporation process, which is charac-.

drying room where itis subjected to hot air at about 130 F. for about 48hours, and when dry, each sheet is separately calendered. Althoughpossessing the advantage of drying at comparatively low tempera ture,whereby the moisture is slowly evaporated, loft drying is obviously veryinciticient and costly, because it requires many separate manipulations,is extremely slow, uses excessive floor space and wastes heat.

The process which is ei'nployed in the ordinary paper machine in commonuse, is likewise subject to many disadvantages. In such machine. the wetpaper as it comes from the paper machine, is passed over many revolvingcylinder heated internally by steam to sufficiently high degree of heat,to raise the temperature of the Water in the paper to 212 l0, theatmospheric boiling point of water. It is customary to supply the dryingcylinders with steam at approximately 5.8 pounds gauge pressure, atwhich the steam has a temperature of 228 F.. giving a difference oftemperature (228-2l2) of only 10 F. \Vith this slight difference oftei'nperature the transfer of heat is extremely slow, and hence it isnecessary to employ many drying Cylinder-s. in board machines often onehundred, and in nevs print machines, forty or more.

Also due to convection and conduction losses, as well as those incidentto leaks in the piping system and other inefficiencies, the heatactually required for atmospheric drying of a ton of wet paper, is verymuch in excess of the theoretical requirement. The thermal etliciency ofatmospheric drying by steam heated cylinders is therefore very low.Furthermore, the steam produced from boiling the water out of the paperis driven off into the operating room, and although fans and exhaustersare employed, at large expense for power and maintenance, the roomatmosphere is so constantly saturated with moisture as to rust andultimately destroy all iron and steel materials, and produces anexceedingly disagreeable and unhealthy atmosphere in which to work. Itis well known that the minimum temperature 212, the atmospheric boilingpoint of water, is positively injurious to. and results in oxidizing,the fibres of the paper, the strength of which is vastly improved whenthe paper is dried at lower temperatures, as in loft dryin Thisatmospheric drying process requires large initial cost for cylinders.felts, and other necessary equipment, and extensive floor space, andresults in the consumption of large amounts of power, and great costforoperation, maintenance and repairs.

In my improved vacuum drying method I contemplate maintaining within thechamber a vacuum of about 28 of mercury, in which water boils at 100 F.,and supplying the drying cylinders with steam at 5.3

pounds gauge pressure, producing a temperature of 228 F. The temperaturedifference between the temperature of the steam in the cylinders andthat of the paper is therefore, 128 F. in my vacuum method, or 8 timesgreater (16X8:128 F.) than the temperature difference in atmosphericdryin In my improved method the paper dries approximately 8 times fasterthan in atmospheric drying, and I require only about one-eighth thenumber of drying cylinders to dry paper at the same rate of speed. I amable to dry paper with 5 cylinders in the same time required of 40cylinders drying at atmospheric pressure, resulting in great economicsin cost of the machine, floor space and of necessary piping, felts,auxiliary equipment, and particularly in power and maintenance charges.

The thermal effioiency of my vacuum method is very much greater thanthat of the atmospheric cylinder drying heretofore in universal use fordrying paper. Theoretically, it requires about 5287 pounds of steam todry one ton of paper at atmospheric pressure, but to compensate forconvection and conduction losses, and those due to leaks in the pipingsystem, and other inefiiciencies, it has been shown in pactice thatabout 10.000 pounds are required.

In my method, using a vacuum of about 28", the convection, conductionand piping losses are exceedingly small and the total steam required todry a ton of paper by my method is approximately 5200 pounds.

It is an established fact that paper dried at low temperatures is muchstronger than when it is dried at the high temperatures used in papermachine atmospheric dryin Paper dried in a vacuum of 28", or at atemperature of about 100 F., as in my method, is very much stronger thanpaper dried at atmospheric pressure, when the steam in the driers is at228 F. When paper is dried by my method, therefore. a cheaper furnish orstock can be used and still produce a paper equal in strength toatmospheric dried paper, in which a higher grade furnish or stock isused. In making newsprint paper, I am able to dispense with aconsiderable portion of the more expensive sulphite pulp, as this can bereplaced with the cheaper ground wood pulp. By my method I also reducethe number of breaks in the web as it passes over the cylinders.

Furthermore, in my method there is a great saving of heat (or steam)because the process is carried on in a vacuum chamber which acts on theprinciple of a thermos bottle, and the steam and vapors driven out ofthe wet paper are caught in the closed vacuum chamber, and conductedaway to the condenser. The operating room is free from steam, humidityand heat, and fans,

'elther heated or not, is blown through the dryer section, which willlower the temrature at which the water is evaporated om the paper much'below 212 F. and may, in some cases, reduce the temperature ofevaporation as low as 180 F. or lower.

Havmg pointed out the many advantages of my method and apparatus overthose heretofore used, it will be apparent that the use of m inventionresults in great econ- -\of the atmosphere.

. her having cm;' in 0 initial cost of apparatus and in arge savings incost of operation, maintenance and repairs.

Having thus described this invention in connection with illustrativeembodiments thereof, to the details of which I do not desire to belimited, what is claimed as new and what is desired to secure by LettersPatent is set forth in the appended claims.

What I claim is: a

1. The method of sealing a vacuum chamber having an opening for theadmission of material mto said vacuum chamber to be treated consistingin preventing admission of air through said 0 ning by causing fluid toflow through sai opening against the pressure of the atmosphere.

2. The method'of sealing a vacuum chamber having an opening for theadmission of material into said vacuum chamber to. be treated consistingin preventing admission of air through said opening by causing quid toflow through said opening against the pressure of the atmosphere.

3. The method of sealing a vacuum-chaman opening for the admission ofmaterial mto said vacuum chamber to be treated consisting through said'ope g against the pressure 4. The method of continuously treating sheetmaterial consisting in continuously feeding it into and out of a vacuumchamher through a fluid moving outwardly with suflicient velocity tohavea pressure equal to or exceedin phere and drylng vacuum chamber.

5. The method of'continuously! drying aweb of wet paper consisting incontinuously feeding the web into and out of a vacuum v in preventingadmission of air through said opening by causing mercury or amalgam orsimilar material to flow the pressureof the. atmos-' the sheet materialin the atmosphere and drying the web of wet paper in the vacuum chamber.7

6. The method of continuously drying a web of wet paper consisting incontinuously feeding the web into and out of a vacuum chamber through aliquid moving outwardly with sufiicient velocity to have a pressureequal to or exceeding the pressure of the atmosphere and drying the webof wet paper in the vacuum chamber.

The method of continuously drying sheet material consisting incontinuously feeding the sheet material in and out of a.

vacuum chamber through a fluid moving outwardly with suflicient velocityto have a pressure equal to or exceeding the pressure of the atmosphere,and protecting the sheet material from contact with the fluid as itpasses through it and drying the sheet material in the vacuum chamber.

8. The method of continuously drying a web of paper consisting incontinuously feeding the web of paper into and out of a vacuum chamberthrough a fluid moving outwardly with suflicient velocity to have apressure equal to or exceeding the pressure of the atmosphere,protecting the web of paper from contact with the fluid as it passesthrough it and drying the web of paper in the vacuum chamber.

9. In a vacuum apparatus the combination of a vacuum chamber having oneor more restricted passages through which the material to be treated ispassed, means to supply a sealing fluid moving outwardly through saidrestricted passage or passages at a suflicient velocity to equal orexceed the atmospheric pressure, so that no air will tion of a vacuumchamber having entrance and exit openings through which the material tobetreated in the vacuum chamber is adapted to pass each opening having apluralit of restricted passages similar to a plura ity of Venturinozzles, and means -to supply fluid through said Venturi nozzles movingoutwardly at suflicient velocity to 'equal or exceed the atmosphericpressure,

so that no air will work into the vacuum chamber and break the vacuumtherein.

of Venturi nozzles connected in series, and

means to supply fluid through said Venturi nozzles moving outwardly-atsuflicient velocity to equal or exceed the atmospheric pressure, so thatno air will work intothe .vacuwork. into the vacuum chamber and break ithe vacuum chamber.

13. The method of sealing a vacuum chamber having openings for thepassage into and out of said chamber of material to be treatedconsisting in preventing admission of air through said opening bysealing said openings with a fluid SLIbJQCtOCl to a pressure outwardlygreater than the pressure inwardly and passing the material to betreated into and out of said vacuum chamber through said fluid.

14. The method of sealing a vacuum chamber having openings for thepassage into and out of said chamber of material to be treatedconsisting in preventing admission of air through said openings bysealing said openings with a liquid under pressure of the atmosphere andalso artiticial pressure, and passing the material to be treated intoand out of said vacuum chamber through said liquid.

15. The method of sealing a vacuum chamber having openings for thepassage into and out of said chamber of material to be treatedconsisting in preventing ads mission of air through said openings bysealing said openings with a fluid subjected to a pressure outwardlygreater than the pressure inwardly, and passing the material to betreated into and out of said vacu um chamber through said fluid andprotecting said material from contact with said fluid as the material ispassed through it.

16. The method of sealing a vacuum chamber having openings for thepassage into and out of said chamber of material to be treatedconsisting in preventing admission of. air through said openings bysealing said openings with a liquid under pressure of the atmosphere andalso artiiicial pressure, and passing the material to be treated intoand out of said vacuum chamber through said liquid and protecting saidmaterial from contact with said liquid as the material is passed throughit.

17. In a vacuum apparatus the combination of a vacuum chamber providedwith one or more restricted passages similar to a Venturi nozzle andthrough which restricted passage or passages the material to be treatedin the vacuum chamber is adapted to pass, and means to force a fluidoutwardly through said restricted passage or passages at sufficientvelocity to prevent the admission of air into the vacuum chamber.

18. The method of continuously drying a web of wet paper consisting incontinuously feeding the web into and out of a vacuum chamber throughmercury, amalgam or similar material, moving with sufficient velocity toprevent the admission of air into the vacuum chamber and drying the webof wet paper in the vacuum chamber.

19. The method of continuously drying a web of wet paper consisting incontinuously feeding the web into and out of a vacuum chamber through afluid which has no aftinity for or deleterious eflect upon said web,said fluid moving with sufficient velocity to prevent the admission ofair into the vacuum chamber and drying the web of wet paper in thevacuum chamber.

20. The method of sealing an entrance or exit opening of a vacuumchamber through which a wet web of paper is fed, said meth od consistingin forcing outwardly through the opening a fluid with suflicientvelocity to prevent the admission of air into the vacuum chamber. c

21. The method of sealing an entrance or exit opening of a vacuumchamber through which a wet web of paper is fed, said method consistingin forcing outwardly through the opening a liquid with suiiicientvelocity to prevent the admissionof air into the vacuum chamber.

22. The method of sealing an entrance or exit opening of a vacuumchamber through which a wet web of paper is fed, said method consistingin forcing outwardly through the opening mercury, amalgam or similarmaterial with suflicient velocity to prevent the admission of air intothe vacuum chamber.

23. The method of sealing an entrance or exit opening of a vacuumchamber through which a wet web of paper is fed, said method consistingin forcing outwardly throu h the opening a fluid with suflicientvelocity to prevent the admission of air into the vacuum chamber andprotecting the wet web of paper as it is fed through said fluid.

24. The method of sealing an entrance or exit opening of a vacuumchamber through which a wet web of paper is fed, said method consistingin forcing outwardly through the opening a liquid with sufficientvelocity to prevent the admission of air into the vacuum chamber andprotecting the wet web of paper as it is fed through the liquid.

25. The method of sealing an entrance or exit opening of a vacuumchamber through which a wet web of paper is fed, said method consistingin forcing outwardly through the opening mercury, amalgam or similarmaterial with suflicient velocity to prevent the admission of air intothe vacuum chamber and protecting the wet web of paper as it is fedthrough the mercury amalgam or similar material.

26. In a vacuum apparatus, the combination of a "acuum chamber havingentrance and exit openings through which the material to he treated inthe vacuum chamber is adapted to pass, each opening having a pluralityof restricted passages similar to a plurality of Venturi nozzles, andmeans to supply fluid through said Venturi nozzles.

27. In a vacuum apparatus the combination of a vacuum chamber havingentrance and exit openings through which the mate rial to be treated inthe vacuum chamber is adapted to pass each opening having a plurality ofrestricted passages similar to a plurality of Vcnturi nozzles, saidplurality of Venturi nozzles connected in series, and means to supplfluid through said Venturi nozzles.

OGDEN MINT ON.

